Aziz, 79, served as foreign minister and deputy prime minister and was a close adviser to the former leader.
He was sentenced to death by the Iraqi Supreme Court in 2010 for the persecution of religious parties under Saddam's rule but was never executed.
He surrendered to US troops in 2003 shortly after the fall of Baghdad.
Aziz, who was known for his black-rimmed glasses and love of cigars, first came to prominence while serving as foreign minister during the first Gulf War in 1991.
As a Christian in a mainly Sunni Muslim government, he was not considered a member of Saddam Hussein's innermost circle.
A fluent English speaker, he played a vocal role before the US invasion of Iraq in 2003, meeting Pope John Paul II in the Vatican to call for peace. » | Friday, June 05, 2015
